1. Field of the Invention
The present invention relates to methods and apparatus for inspection and review of semiconductor wafers and other manufactured substrates.
2. Description of the Background Art
An automated defect review system generally receives a defect location that is determined previously by an automated inspection system. The inspection system may determine the defect location using bright or dark field optical imaging or by electron beam imaging.
The defect review system may then use a scanning electron microscope (SEM) having a pre-set electron beam configuration, usually in a secondary electron mode, to obtain an image at the defect location. However, there are almost always some defects that are detected by the inspection system but do not show up (i.e. are not visible to) the review system. These defects are conventionally classified as SEM non-visible (SNV) defects.